Hello there,,,,well there are a number of reasons for back pain,,,,it could be as simple as a muscle spasm or could be more complicated than that....hence proper guidance,advice,treatment is necessary.
You have pain since 4 years hence your pain is chronic.
Do upload your xray/mri , blood reports so that the exact cause could be found out and proper treatment could be started
Next Steps
You are a young lad,,,dont delay.
Regards
Dr Raviraj Francis
MPTh(Rehab).MPT(MSk)UK.